Lathe-dog.



` @Magg '11. R. PENN.-

LATER nos. APPLICATION FILED MAB. 26. 1907.

PATENTED DEG. 24, '1907.

frana nieren ROSS R. PENN, OF FLORA, INDIANA.

Lamm-noe.

Specification of Letters Patent.

Fatented Bee. 21.3., 1907.

Application filed March Z6; 1907. Serial No. 364,i'43.

To all lwhom 'it may concern:

Be 1t known that l, Ross R. PENN, a citi- 'zen of the United States, residing at Flora, in

the county of Carroll and State of Indiana,

vhave invented new and useful Im rovements in Lathe-Dogs, of which the fol owing is a specification.

` or wrench This invention relates to im rovements in lathe dogs, wrenches and simi ar 'tools of the type provided with jaws to grip the work or object to beheld or turned. l

The object of the invention is to provide a simple and effective device of this character in which the jaws vlare self-adjusting in either;- direction of movement of the tool to grip objects varying to a greater or less de ree in size and to regulate their rip accor ing to the amount of resistance ot the object to be held or turned.y

A further .object is to provide jaws which are readily removable forrenewal and are reversible, so that.` unworn portions of the gripping surfaces may be presented for use in ieu of the worn surfaces.

With the above and other objects in view, the invention consists of the novel construction, combinatien andarrangement of parts, hereinafter fully described and'claimed, rjeference being had to the accompanying drawing, in which-i j Figure 1 is abide' elevation of a lathe dbg embodying *my invention. Figiv 2 is 'a reverse sidejelevation of the same. Fig. 3 is a plan view with the head and jaws `1in longitudinal section. l

l eferring to the drawing, l designates the shank of the tool provided at its forward end with a head, holding-iron orring 2, within which are arranged the gripping jaws 3 and 4. The inner wall of the head 2 is of oblong form to provide front and rear surfaces 5 and 6 which are curved on arcs eccentric to axis of the head, and intervening upper and lower surfaces 7 and 8 which may be curved on arcs concentric with the axis cf the head, or have a less fdegree of eccentric curvature than the surfaces 5 and 6. The pairs or sets of surfaces 5, and 6 7 and 8 are arranged diametrically op "osite each other, the one setin a plane at riglt angles to the other, as clearly shown. Thisjspecitic arrangement may, of course, be varied', that is to say, the sets? of surfaces may fbe reversed in relative arrangement on the ,fl1ead, as circumstances mayj require.

curved on arcs to correspond with the surfaces 5 and 6 and normally bear against the same while the inner faces of said jaws ma curve in a true arc and are-preferably eac provided with an inner row of vtt-sha ed gripping teeth or serrations 9, although t ey may be smooth-surfaced or formed with gripping portions of adapt them for engagement with: any particular tjpe of object. Each jaw is provided at one si e with a retainingflange L() to bear against one side of the holding-ring or head 2, and extends at itsopposite the opposite side of the head. On said opposite side are provided holdin devices 1l,-

which may be inthe nature of or inary screws engaging threaded openings therein, the heads of the screws being arranged to engage the side of the ring opposite the flanges 10 to coperate with saidiV fianges in rholding the jaws against. lateral or outward movement. The screws lightly 'engage the sides .ofthe jaws, so as to permit the latter to slide or turn within the ring for self-gripping adjustment. 4 j

ln the operation of the device, the object to be gri ped and held or turned is arranged to exten through the head between the jaws and the tool turned by means of the shank 1. The gripping surfaces of the jaws are intended primarily to lightly engage the surface of the object, and in turning the tool the jaws ride in unison in the head partially out of ene gagement with the surfaces and 6 and into engagement with the surfaces 7 and 8, a cam action thereby being induced, whereby the jaws are forced inwardly into gripping engagement with the object. The degree to 'which the jaws will turn depends upon the resistance of the object, and consequently the greater the resistance, the greater the ex of independent movement of the head around the jaws, until the latter firmly gri the pipe and a binding action is institute between the head and the jaws, whereupon the object will be iirinly held. A reverse mevement of the tool will, of course,l relax the jaws, leaving the tool -free to be slipped ed the object, or the latter to be removedfrom the head. This action will occur in the movement of the tool in either direction, that is, either backward or forward, until a frictional binding or locking action isl effected, when the object any preferred character to side Hush with tent of movement of the jaws, or the degree Vcome worn, uponlrem'ovinrthe screws 11 the 'ring to engage the jaws when set to grip an may be grip ed and held stationary or I turned, accor ing to the character of Work to l be performed. By the'provision of rl-shaped teeth the points of the teeth will impinge against the object in either direction of movement of the handle, and by the simple form and arrangement ofthe cam surfaces employed it willbelseen thata self-adjusting aetion of the jaws is secured in an eil'eetive manner Without employing extraneous ele-, ments or increasing the cost of the tool to any material extent .e j

When the tool has been `employed for any material length of time in gripping and turning objects in one direction and the sides of the teeth facingin such direction have bejaws may be detached and reversed, so as to resent o )positc or unworn teeth of the jaws or use, tlaus increasing the elliciency of the tool. `This mode of mounting the jaws in place also permits of their ready removal when Worn for the substitution ol new jaws therefor. e

The principles of the invention may be employed in machinists lathe dogs, pipe and rod wrenches and other tools. If desired, binding screws l2 may be employed uponl the object to hold them lixed against loosening or slipping under any casual retrograde movement of the tool.

Having thus described the invention, what is claimed as new, is-zi l. A tool of the character described comprising a shank havingl a ring-shaped'` head providing cam surfaces, jaws slidably mount` 'having cam walls, jaws slidably engaging said walls, said jaws being provided at one sideI with retaining flanges engaging one side ol the head, and retaining screws on the opposite side of the jaws engaging the reverse side of the head, said screws being removable to permit lateral detachment el the jaws,

ln testimony whereof l a'ilix my signature in presence of two witnesses.

ROSS l. PENN.

Titnesses 1. J. BRION, ELMnR M. EIKENBERG. 

